Silane modified, alkylene-alkyl acrylate copolymers, as described in my U.S. Pat. No. 4,328,323 granted May 4, 1982, are particularly desirable for use in commercial applications as these copolymers and compositions based thereon can be cured by a simple water treatment, as opposed to the more conventional peroxide curing. As a result, silane modified alkylene-alkyl acrylate copolymers and compositions based thereon are especially useful in extrusion applications, being capable of extrusion under a wide latitude of processing conditions.
The production of water curable, silane modified alkylene-alkyl acrylate copolymers is conveniently carried out by reacting a mixture containing a polysiloxane, an alkylene-alkyl acrylate copolymer and organo titanate with the result that the polysiloxane reacts with the alkylene-alkyl acrylate copolymer, the reaction being catalyzed by the organo titanate.
In carrying out the reaction, care must be taken to protect the polysiloxane from moisture. Polysiloxanes hydrolyze rapidly on contact with moisture and crosslink to gelled products, which for all practical purposes, are useless. Furthermore, the problem associated with moisture is accentuated when the formulations of the compositions include hydrous or water-releasing fillers which, through reaction or catalysis cause the compositions to prematurely crosslink. Premature cross-linking, commonly referred to as scorch, usually occurs in the extruder wherein the compositions are processed, undergo a reaction and are extruded about wires and cables. In extreme cases, scorching necessitates stopping of the extrusion operation and cleaning of the extruder.